Age at calving in heifers and level of milk production during gestation in cows are associated with the birth size of Holstein calves

Abstract

The objective of the present study was to evaluate environmental and dam factors associated with birth size of Holstein calves. Data of 1,594 births from dairy herds in Belgium and Germany were analyzed in a retrospective cross-sectional study. Immediately after birth, the birth weight of the calves was measured. On the next day, the heart girth (HG), withers height, and diagonal length of the dams and calves were measured. Parity, body condition score, gestation length (GL), and age at calving were recorded for all dams. For the cows, days open, lactation length, length of the dry period, and calving interval were also calculated. The magnitude and shape of the lactation that took place during gestation was quantified using the MilkBot model based on monthly milk weights. Using the same procedure, cumulative milk production from conception to drying off (MGEST) was calculated. After descriptive analyses, mixed models were used to identify factors that are significantly associated with the birth weight (most consistent measure of size at birth) of the calves born to both heifers and cows. Of the variables offered to the offspring birth weight model in heifers (n=540), calf sex, season of calving, GL, HG, withers height, diagonal length, and age at calving were significant. The mean birth weight of the calves born to heifers was estimated to be 41.3±1.01kg. In comparison to calves born to old (25.5 to 37.3mo; n=99) heifers, the birth weight was estimated to be 2.75, 3.29, and 2.35kg heavier when the calves were born to very young (20.3 to <22mo; n=98), young (22 to <23.5mo; n=145), and standard aged (23.5 to <25.5mo; n=198) heifers, respectively. Of the variables offered to the offspring birth weight model in cows (n=1,054), calf sex, season of calving, GL, parity, dry period, and MGEST were significant. The mean birth weight of the calves born to cows was estimated to be 44.1±0.99kg. For cows having an identical HG, the birth weight of the calves was estimated to be 0.97 and 1.11kg higher in cows with low (1,400 to <5,400kg) and high (6,500 to <7,200) MGEST, respectively, compared with cows with very high (7,200 to 11,600kg) MGEST. The decisive effects of age at calving in heifers and of high milk production levels during gestation in cows on the birth weight of their calves may provide a basis for developing managerial interventions to improve long-term health and productivity of the offspring.

Risk factors associated with dystocia in a tie stall dairy herd

“…However, the prevalence of dystocia and stillbirth remain unacceptably high, and inappropriate sire selection seems to be a big part of the problem. Contrary to results from Kamal et al (2014), AGE of heifers and DIM of multiparous cows at conception were not related to CBW. Moreover, there was no significant effect of AGE or DIM on GL or dystocia.…”

“…Indeed, age at first parturition (AGE) and milk production during gestation of lactating dairy cows have recently been associated with CBW (Kamal et al 2014), probably due to energy partitioning between growth (heifers), and intrauterine growth of the fetus. However, the effect of days in milk at conception on calvingrelated disorders is unknown (Ingvartsen et al 2003).…”

Evidence for placental compensation in cattle

“…These results correspond with the research of Kamal et al (2014), who found age at first calving in HF heifers and milk yield in HF cows to be better predictors of calf size than body measurements. The latter implies that, although larger dams are believed to have a larger uterus (Allen et al, 2002) and a higher feed intake, the fetus is not directly benefitting from this advantage, which suggests other maternal tissues to have a higher priority in terms of nutrient partitioning.…”

Environmental and maternal factors associated with gross placental morphology in dairy cattle

“…The former implies that gestation in primiparous animals should take place when dams are still growing, while the latter implies that in multiparous animals, gestation should to a large extent coincide with lactation. Recently, we have demonstrated that young age at first gestation and a high level of milk yield during gestation in multiparous dams both reduce intrauterine foetal development, probably by diverting a significant proportion of nutrients to dam growth and milk production (Kamal et al., ). Subsequently, we have demonstrated that both growth and lactation during gestation have a significant impact on gross placental morphology in cattle (Van Eetvelde et al., ).…”